No much gain on this particular case, however, when using iterators and other verbose types, it really helps readability.

The change should be discussed with the main developers to reach a consensus. VTK and ITK are using auto in a lot of cases.

Move not implemented constructors and assignment operators to the public interface

Now that we use = delete, we don't need the constructors and assignment operator to be in the private interface.
Moving them to the public interface is better. Including better integrations with IDE's.